ANOMALOUS MAGNETIC-PROPERTIES OF THE 2212-TYPE RARE-EARTH CUPRATES BI2SR2RCU2O8+DELTA (R=PR, GD, Y)

An anomalous high antiferromagnetic Neel temperature T-N(Pr) of 8 K ar e reported for the argon-treated Bi-2212 compound Bi2Sr2PrCu2O8+delta. In this compound, a high Cu ordering temperature T-N(Cu) of 350 K was also observed. For the isostructural Gd compound Bi2Sr2GdCu2O8+delta, a Curie-Weiss paramagnetic intercept theta(p) of -2.5 K is consistent with antiferromagnetic T-N(Gd) of 1.8 K reported before. For non-magn etic Y compound Bi2Sr2YCu2O8+delta, only Cu ordering around 350 K was observed.